Messages in this thread Patch in this message | | | Date | Wed, 06 May 2009 21:36:16 -0700 | From | Yinghai Lu <> | Subject | [PATCH] x86: fix compute high_width with phys-addr is 44bit and more |
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found one system that cpu address line is 44bits, mtrr printout is not right.
[ 0.000000] MTRR variable ranges enabled: [ 0.000000] 0 base 0 00000000 mask FF0 00000000 write-back [ 0.000000] 1 base 10 00000000 mask FFF 80000000 write-back [ 0.000000] 2 base 0 80000000 mask FFF 80000000 uncachable [ 0.000000] 3 base 0 7F800000 mask FFF FF800000 uncachable
Li Zefan and Frederic pointed out the high_width could be -4 some how.
it turns out when phys_addr is 44bit, size_or_mask will be ffffffff,00000000 so ffs(size_or_mask) will be 0.
try to check low 32 bit, to get correct high_width.
Signed-off-by: Yinghai Lu <yinghai@kerne.org> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Frederic Weisbecker <fweisbec@gmail.com>
--- arch/x86/kernel/cpu/mtrr/generic.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
Index: linux-2.6/arch/x86/kernel/cpu/mtrr/generic.c =================================================================== --- linux-2.6.orig/arch/x86/kernel/cpu/mtrr/generic.c +++ linux-2.6/arch/x86/kernel/cpu/mtrr/generic.c @@ -275,7 +275,11 @@ static void __init print_mtrr_state(void } printk(KERN_DEBUG "MTRR variable ranges %sabled:\n", mtrr_state.enabled & 2 ? "en" : "dis"); - high_width = ((size_or_mask ? ffs(size_or_mask) - 1 : 32) - (32 - PAGE_SHIFT) + 3) / 4; + if (size_or_mask & 0xffffffffUL) + high_width = ffs(size_or_mask & 0xffffffffUL) - 1; + else + high_width = ffs(size_or_mask>>32) + 32 - 1; + high_width = (high_width - (32 - PAGE_SHIFT) + 3) / 4; for (i = 0; i < num_var_ranges; ++i) { if (mtrr_state.var_ranges[i].mask_lo & (1 << 11)) printk(KERN_DEBUG " %u base %0*X%05X000 mask %0*X%05X000 %s\n",
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